The present invention relates to an improved undercarriage for mobile X-ray diagnostic equipment, and in particular to a combination of balance, brake and swivelling devices of the undercarriage which provide enhanced control over the equipment during movement thereof.
Large medical diagnostic equipment such as X-ray machines serve an important part in the medical community's ability to diagnose and treat disease. The expense of these machines, however, places limitations on the number that a hospital or other medical facility can afford to purchase. Thus, hospitals often use mobile equipment which can be moved from one place to another as needed, alleviating the need for having a machine at every diagnostic location.
The movement of this equipment, however, raises numerous problems due to the equipment's size and weight. A C-arm X-ray machine, for example, can weigh in excess of six hundred pounds. Additionally, the C-arm portion of such equipment is usually about six feet tall, six feet long, and three feet wide. Because of the size and weight of the equipment, the only practical means for moving it is to provide wheels on the base of the machine.
These wheels are often designed to swivel to facilitate turning the equipment within a room or hallway, but such swiveling wheels can themselves cause problems. For example, if the equipment is moved too quickly, or on surface that is sloped, the wheels may turn slightly, causing the equipment to drift to one side or even turn sideways. This, in turn, may result in the equipment tipping over and being damaged.
Additionally, the method for moving the X-ray C-arm must be adjustable to provide precise movement when in use. Some surgical procedures require that numerous X-rays be taken in the same place, and some require X-rays to be taken at various points along the patient's body. The C-arm's base must include mechanisms to allow the C-arm to be held in a fixed position when desired, and to move in a relatively straight line (forward and back or to either side) when necessary. Additionally, the equipment must be easily movable without interfering with the medical personnel in the operating room.
An improved undercarriage supporting the C-arm would allow the wheels to swivel when desired, while allowing the user to lock the wheels in one or more directional orientations either to avoid lateral drift when transporting the equipment or force the equipment along a linear path perpendicular to the length of the machine during a surgical procedure. An improved undercarriage would also allow the wheels to be locked to keep the equipment in place while allowing simple and quick release of the lock so that the equipment may be moved out of the way.
Bumps and uneven surfaces in hospital hallways cause other problems in moving large diagnostic equipment. A small bump such as the base of a door frame can create a significant problem for those moving X-ray C-arms and other large machines. Due to the equipment's weight, it is difficult to lift the front wheels of the undercarriage over even these small bumps. To solve the problem, the rear wheels of the undercarriage are commonly placed as close as possible to the center of gravity of the equipment to facilitate lifting of the front wheels when needed. This positioning, however, renders the equipment less stable. With such an arrangement, an unexpected bump can cause the front wheels to rise, shifting the equipment's center of gravity and causing the equipment to rock backwards, jarring the equipment and potentially injuring the feet or legs of those moving the machine.
In an attempt to solve this problem, prior innovators have placed stoppers near the back of the undercarriage to prevent the equipment from rocking backwards. The stoppers, however, interfere with certain movements of the machine, such as when it is necessary to roll the machine up an incline. As the front wheels rise up the incline, the machine pivots backward, the stoppers grip the floor, and the machine is prevented from forward movement. An improved undercarriage is needed which allows the equipment to pass over obstacles and roll up inclines, while preventing the equipment from suddenly rocking backwards.